Conventionally, when anomaly occurs at a vehicle, information about the anomaly is transmitted from the vehicle to an external information center automatically. For example, in an information service system disclosed in JP-A-H10-297446, a communication ECU mounted on the vehicle periodically communicates with other ECU so that the communication ECU monitors function of the other ECU. When the other ECU does not function normally, the communication ECU transmits a data to the information service center. Thus, the information service center can specify function at which the anomaly occurs. Further, the center partially or fully carries out the function for the other ECU.
When the ECU detects the anomaly of the vehicle, a chattering may occur so that a case where the anomaly is detected and a case where the anomaly is not detected are alternately switched at frequent intervals. For example, when anomaly is detected based on a liquid level of oil or window washer fluid, a state in which the anomaly is not detected may be switched to a state in which the anomaly is temporally detected, or a state in which the anomaly is detected may be switched to a state in which the anomaly is not temporally detected, since a tilt of the vehicle on a sloping road affects the liquid level. Thus, it is not appropriate to determine based on the anomaly detection whether the anomaly actually occurs.
Thus, it is preferable to determine the actual anomaly occurrence when the state, in which the anomaly is detected, continues for a predetermined period. Similarly, it is preferable to determine the anomaly is resolved (i.e., recovered) after the actual anomaly occurrence when the state, in which the anomaly is not detected, continues for a predetermined period.
Here, it is preferred that the predetermined period is set to be longer in view of the influence of the chattering. On the other hand, it is important to notice the anomaly immediately. Accordingly, the period for determining the actual anomaly occurrence is set to be a comparative short time such as 8 seconds. The period for determining the recovery from the anomaly is set to be a comparative long time such as 10 trips. Here, the definition of the trip is a period between a switch on time and a following switch on time.
For example, as shown in FIG. 4A, a failure detection device for a vehicle confirms a detection result that the failure occurs when the device receives the same failure occurrence result continuously for a predetermined period IVA such as 8 seconds. Then, the device notices the failure. After that, the device confirms the detection result that the failure is resolved when the device determines that a state, in which the failure detection is not received, continues for a predetermined period IVB such as 10 trips.
Thus, a dealer for repairing vehicles can preliminary receives failure information of the vehicle from an information center so that the dealer prepares for the repair. The repair of the vehicle can be performed effectively.
However, as shown in FIG. 4B, failure may occur again after an owner of, the vehicle receives the repaired vehicle from the dealer. In this case, the failure may not be informed to the information center. Specifically, the failure may occur again before the device determines that the state, in which the failure detection is not received, continues for the predetermined period IVB. That is, the failure may occur again before the device confirms the resolution of the failure. In this case, the device misjudges that the failure continues.
Thus, it is required to inform the occurrence of anomaly accurately after the vehicle is repaired.